What causes skin allergy
Hives are an outbreak of swollen, pale red bumps that appear suddenly on the skin.
These bumps are sometimes called wheals or welts, and they may be circular or irregular in shape and range in size from pin-size dots to large map-like patches.
They can appear anywhere on the body, including the face, lips, tongue, throat, or ears. Their edges are distinct, and the area of skin affected by the hive is smooth and elevated above the surrounding area of skin (reflecting the fluid collected in the layer of skin under the surface).
Angioedema is similar to hives, but the swelling occurs deeper within the skin instead of on the surface, so the swelling is more noticeable and worrying.
Occasionally, angioedema can be life-threatening, because the swelling can happen around the throat, tongue or lungs and restrict breathing. Other common areas affected by angioedema include the eyes, lips and sometimes the genitals, hands, or feet. See your doctor as soon as possible if you develop angioedema.
Some wheals may glance diverse from others, for example, some may be red, whereas others may be pale; some may be rounded, whereas others may be flat on top. Hives are generally incredibly itchy and they characteristically change in size and shape and may join together to form larger areas known as plaques.
Sometimes they vanish for a few hours only to reappear in a diverse formation later.
Most people ponder hives are caused by an allergy, but in fact, most cases of hives happen for non-allergic reasons, although allergies are a common cause. Other causes of hives include:
- Medications (such as aspirin, NSAIDs [eg, ibuprofen], ACE inhibitors, codeine, sulfa drugs)
- Physical stimuli, such as pressure, freezing, heat, exercise or sun exposure
- Insect bites or stings
- Chemicals in certain foods (such as additives and preservatives)
- Blood transfusions
- Infections (eg, colds, infectious mononucleosis, hepatitis, urinary tract infections, and strep throat)
- Certain foods: The most common foods implicated are nuts, chocolate, fish, tomatoes, eggs, unused berries, and milk.
Unused foods cause hives more often than cooked foods
- An underlying internal disease (such as thyroid disease, cancer, or hepatitis).
Hives (urticaria) are generally classified as acute (lasting less than six weeks) or chronic (lasting more than six weeks). Some cases are mild, while others are severe. Scratching, alcoholic beverages, exercise, and stress may worsen hives.
The most frequently recommended treatment for hives is antihistamines. These work by blocking the effect of histamine, which is a chemical in the skin that can cause inflammation, swelling, and itching. Freezing compresses or anti-itch salves may also assist ease symptoms.
The main difference between hives and a rash is that hives are a particular type of rash, characterized by swollen, pale-red or skin-colored bumps on the skin that appear and vanish quickly, and tend to “blanch” (which means turn white) when pressed.
Hives are also known as urticaria.
Hives are a type of rash, but there are numerous other diverse ways rashes present. Both hives and rashes tend to be itchy.
There are several diverse types of skin allergies such as allergic contact dermatitis, urticaria (hives) and photoallergy. Clinical symptoms for allergic contact dermatitis often happen 1-2 days after exposure to an allergen. Photoallergy symptoms may happen somewhat earlier than allergic contact dermatitis.
Urticaria often occurs within minutes after exposure.
The most common causes of skin allergies are exposure to metals and chemicals that can penetrate the skin, but proteins may also cause skin allergy. These substances are present in consumer products such as cosmetics and body care products, hair dyes, detergents, textiles and jewellery. The most common contact allergens are nickel, fragrances and thimerosal (preservative). Approximately 20% of the population has a contact allergy.
Certain occupational groups are particularly vulnerable to developing skin allergies. These are professions with frequent hand washing and work with irritant and sensitising agents (e.g. rubber chemicals, fragrances, preservatives, dyes, metals).
Atopic dermatitis (sometimes called infantile eczema) is a chronic disease with an itchy rash that often appears in early childhood.
About 70% of children with atopic eczema grow out of it before adolescence.
The trigger factors are unclear, but children with allergic and asthmatic parents own an increased risk of developing atopic dermatitis. A combination of genes and environment seems to be important.
Food allergy is a significant public health problem and is reported to affect 3-4% of adults and 6-8% of children in Europe, with an increasing incidence among children.
Changes in eating habits, with new imported products, more processed foods and increased travel can also own contributed to food reactions becoming more common.
Food allergy occurs most often in those who own atopic diseases, such as atopic dermatitis, asthma andhay fever.
Allergy is defined as an immunological response and is limited to food reactions that can be confirmed by immunological methods such as the detection of IgE antibodies in serum. Food allergies are triggered by food proteins and generally cause quick reactions. These reactions happen because the natural tolerance is broken. Symptoms are commonly seen in other organs than the stomach and intestines, such as the skin, the respiratory system and the cardiovascular system.
Hypersensitivity reactions generally cause intestinal symptoms. Common food allergens include legumes such as peanuts and nuts, flour, fish and shellfish. Cow’s milk, wheat and eggs often trigger allergies among children, but they generally grow out of these allergies by school age.
The incidence of severe reactions to food in Norway is unknown. In 2000, the National Register of Severe Allergic Reactions to Food was established to increase knowledge, and doctors own been encouraged to report severe patient reactions. As from January 1st 2018 the Register is no longer in operation.
What is a rash?
A rash is an irritated area of skin. Most rashes are characterized by little bumps of skin, are itchy and glance red.
Sometimes the skin may be broken from scratching. In some types of rashes, blisters may form.
Rashes may be a symptom of an underlying medical problem and some people are more likely than others to develop rashes. Other common causes of rashes include:
- Plants (eg, poison ivy)
- Irritating substances
- Medications (eg, amoxicillin, sulfa drugs)
- Insects, spiders, or jellyfish
- Chemical exposure
Some rashes develop suddenly, whereas others form over several days.
Treatments vary, depending on what caused the rash in the first put but may include moisturizers, lotions, corticosteroids creams (which relieve redness and swelling) and antihistamines (which relieve redness and itching).
If your rash doesn’t go away within a few days, you own other worrying symptoms, or is extremely severe, see your health care provider.
What Are the Symptoms of an Allergy?
An allergy occurs when the body’s immune system sees a substance as harmful and overreacts to it. The symptoms that result are an allergic reaction. The substances that cause allergic reactions are allergens.
Allergens can get into your body numerous ways to cause an allergic reaction.
- Your body can own allergens injected into it. This includes medicine given by needle and venom from insect stings and bites.
- You can ingest allergens by mouth. This includes food and medicines you eat or swallow.
- You can inhale allergens into your nose and your lungs. Many are little enough to float through the air. Examples are pollen, home dust, mold spores, cat and dog dander and latex dust.
- Your skin can absorb allergens. Plants such as poison ivy, sumac and oak can cause reactions when touched. Latex, metals, and ingredients in beauty care and household products are other examples.
Undesirable effects from the use of cosmetic products often happen.
These include soap, shampoo, moisturisers, deodorants, shaving products and make-up. Undesirable effects include allergies, rashes, blisters, burning or other symptoms.
The products that cause most problems are fragrances, preservatives and hair dyes. Preservatives and fragrances can cause adverse effects, particularly in the form of rashes and other skin reactions.
Respiratory allergies are caused by proteins in the air that are inhaled and trigger airway inflammation. They may be due to specific allergic reactions, or more general reactions to irritants such as smoke and fumes in the indoor and outdoor environment that can aggravate allergy symptoms.
There are numerous sources of respiratory allergies; home dust contains various components such as dust mites, pet allergens, pollen and particulates that can trigger asthma and allergies.
If humidity is too high, mould growth can happen, and the quantity of mould spores containing allergens will increase.
Home dust mites thrive wherever it is boiling and humid, especially in mattresses and bedding. Mite faeces are the main cause of allergies. Pet allergens generally come from proteins from animal skin, fur, urine and saliva.
The allergens often sit on little particles that can stay aloft for a endless time and thus spread over large areas.
The increase in allergic diseases may be related to climate change. A warmer climate leads to a longer pollen season and therefore an increased incidence of respiratory allergies. Pollen can cause cross-allergies because there are similar proteins in pollen and plant foods such as fruits, vegetables and nuts, which will also increase allergic reactions to food.
Cross allergies, however, cause milder symptoms than primary allergies.